Understanding Impeachment

Attorneys seek to discredit opposing witnesses in various ways, including impeachment. Impeachment can be a very powerful tool for attorneys if executed properly, and extremely damaging to an expert witness’s credibility. Don’t get caught off guard– be aware that opposing counsel will try to impeach if given the opportunity.

Rules To Impeach:

The impeaching statement must be inconsistent with some part of either the express or implied testimony of the witness (Evid C §§770, 1235); and either (1) the witness, while testifying, was given an opportunity to explain or deny making the prior inconsistent statement (Evid C §770), or (2) the witness has not been excused from giving further testimony in the action (Evid C §770); and

If the impeaching statement is a writing, it must be authenticated (Evid C §1401).

The witness has an opportunity to explain or deny the point of dispute.

Explain clearly why answers have changed between current testimony and past depositions.

Be aware of your tone of voice. Refrain from becoming argumentative or defensive towards counsel. A level and calm tone will help the jury perceive you are confident with your current position while explaining why your opinion has changed.